/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.catalina.loader;

import org.apache.catalina.LifecycleException;

import java.io.File;
import java.util.*;

/**
 * A WebappLoader that allows a customized classpath to be added
 * through configuration in context xml. Any additional classpath entry will be
 * added to the default webapp classpath, making easy to emulate a standard
 * webapp without the need for assembly all the webapp dependencies as jars in
 * WEB-INF/lib.
 * <p>
 * <pre>
 * &lt;Context docBase="\webapps\mydocbase">
 *   &lt;Loader className="org.apache.catalina.loader.VirtualWebappLoader"
 *              virtualClasspath="/dir/classes;/somedir/somejar.jar;
 *                /somedir/*.jar"/>
 * &lt;/Context>
 * </pre>
 * <p>
 * <p>The <code>*.jar</code> suffix can be used to include all JAR files in a
 * certain directory. If a file or a directory does not exist, it will be
 * skipped.
 * </p>
 *
 * @author Fabrizio Giustina
 */
public class VirtualWebappLoader extends WebappLoader {

	private static final org.apache.juli.logging.Log log =
			org.apache.juli.logging.LogFactory.getLog(VirtualWebappLoader.class);

	/**
	 * <code>;</code> separated list of additional path elements.
	 */
	private String virtualClasspath = "";

	/**
	 * Construct a new WebappLoader with no defined parent class loader (so that
	 * the actual parent will be the system class loader).
	 */
	public VirtualWebappLoader() {
		super();
	}

	/**
	 * Construct a new WebappLoader with the specified class loader to be
	 * defined as the parent of the ClassLoader we ultimately create.
	 *
	 * @param parent The parent class loader
	 */
	public VirtualWebappLoader(ClassLoader parent) {
		super(parent);
	}

	/**
	 * <code>virtualClasspath</code> attribute that will be automatically set
	 * from the <code>Context</code> <code>virtualClasspath</code> attribute
	 * from the context xml file.
	 *
	 * @param path <code>;</code> separated list of path elements.
	 */
	public void setVirtualClasspath(String path) {
		virtualClasspath = path;
	}

	/**
	 * @return Returns searchVirtualFirst.
	 */
	public boolean getSearchVirtualFirst() {
		return getSearchExternalFirst();
	}

	/**
	 * @param searchVirtualFirst Whether the virtual class path should be searched before the webapp
	 */
	public void setSearchVirtualFirst(boolean searchVirtualFirst) {
		setSearchExternalFirst(searchVirtualFirst);
	}

	/**
	 * Implement the requirements
	 * of {@link org.apache.catalina.util.LifecycleBase#startInternal()}.
	 *
	 * @throws LifecycleException if this component detects a fatal error
	 *                            that prevents this component from being used
	 */
	@Override
	protected void startInternal() throws LifecycleException {

		// just add any jar/directory set in virtual classpath to the
		// repositories list before calling start on the standard WebappLoader
		StringTokenizer tkn = new StringTokenizer(virtualClasspath, ";");
		Set<String> set = new LinkedHashSet<String>();
		while (tkn.hasMoreTokens()) {
			String token = tkn.nextToken().trim();

			if (token.isEmpty()) {
				continue;
			}

			if (log.isDebugEnabled())
				log.debug(sm.getString("virtualWebappLoader.token", token));

			if (token.endsWith("*.jar")) {
				// glob
				token = token.substring(0, token.length() - "*.jar".length());

				File directory = new File(token);
				if (!directory.isDirectory()) {
					if (log.isDebugEnabled()) {
						log.debug(sm.getString(
								"virtualWebappLoader.token.notDirectory",
								directory.getAbsolutePath()));
					}
					continue;
				}
				if (log.isDebugEnabled()) {
					log.debug(sm.getString(
							"virtualWebappLoader.token.glob.dir",
							directory.getAbsolutePath()));
				}
				String filenames[] = directory.list();
				Arrays.sort(filenames);
				for (int j = 0; j < filenames.length; j++) {
					String filename = filenames[j].toLowerCase(Locale.ENGLISH);
					if (!filename.endsWith(".jar"))
						continue;
					File file = new File(directory, filenames[j]);
					if (!file.isFile()) {
						if (log.isDebugEnabled()) {
							log.debug(sm.getString(
									"virtualWebappLoader.token.notFile",
									file.getAbsolutePath()));
						}
						continue;
					}
					if (log.isDebugEnabled()) {
						log.debug(sm.getString(
								"virtualWebappLoader.token.file",
								file.getAbsolutePath()));
					}
					set.add(file.toURI().toString());
				}
			} else {
				// single file or directory
				File file = new File(token);
				if (!file.exists()) {
					if (log.isDebugEnabled()) {
						log.debug(sm.getString(
								"virtualWebappLoader.token.notExists",
								file.getAbsolutePath()));
					}
					continue;
				}
				if (log.isDebugEnabled()) {
					log.debug(sm.getString(
							"virtualWebappLoader.token.file",
							file.getAbsolutePath()));
				}
				set.add(file.toURI().toString());
			}
		}

		for (String repository : set) {
			addRepository(repository);
		}

		super.startInternal();
	}

}
